From 4ab77697f67aa5b90b032b9175b46901859da6d7 Mon Sep 17 00:00:00 2001 From: Amit Kapila Date: Tue, 1 Sep 2020 08:11:39 +0530 Subject: [PATCH] Fix the SharedFileSetUnregister API. Commit 808e13b282 introduced a few APIs to extend the existing Buffile interface. In SharedFileSetDeleteOnProcExit, it tries to delete the list element while traversing the list with 'foreach' construct which makes the behavior of list traversal unpredictable. Author: Amit Kapila Reviewed-by: Dilip Kumar Tested-by: Dilip Kumar and Neha Sharma Discussion: https://postgr.es/m/CAA4eK1JhLatVcQ2OvwA_3s0ih6Hx9+kZbq107cXVsSWWukH7vA@mail.gmail.com --- src/backend/storage/file/sharedfileset.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c index 8b96e81ffff..859c22e79b6 100644 --- a/src/backend/storage/file/sharedfileset.c +++ b/src/backend/storage/file/sharedfileset.c @@ -266,12 +266,16 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum) static void SharedFileSetDeleteOnProcExit(int status, Datum arg) { - ListCell *l; - - /* Loop over all the pending shared fileset entry */ - foreach(l, filesetlist) + /* + * Remove all the pending shared fileset entries. We don't use foreach() here + * because SharedFileSetDeleteAll will remove the current element in + * filesetlist. Though we have used foreach_delete_current() to remove the + * element from filesetlist it could only fix up the state of one of the + * loops, see SharedFileSetUnregister. + */ + while (list_length(filesetlist) > 0) { - SharedFileSet *fileset = (SharedFileSet *) lfirst(l); + SharedFileSet *fileset = (SharedFileSet *) linitial(filesetlist); SharedFileSetDeleteAll(fileset); } @@ -301,7 +305,7 @@ SharedFileSetUnregister(SharedFileSet *input_fileset) /* Remove the entry from the list */ if (input_fileset == fileset) { - filesetlist = list_delete_cell(filesetlist, l); + filesetlist = foreach_delete_current(filesetlist, l); return; } }